Process of making chambered articles containing a movable element



Feb. 10, 1953 HALLER PROCESS OF MAKING CHAMBERED ARTICLES CONTAINING A MOVABLE ELEMENT Filed Feb. 28.

INVENTOR ATTORNEYS Patented Feb. 10, 1953 UNITED STATES PROCESS F MAKING CHAMBERED ARTI- CLES CONTAINING A MOVABLE ELEMENT 10 Claims. 1

This invention relates to powder metallurgy, and in particular to processes of making chambered articles employing powdered metal.

One object of this invention is to provide a process of making chambered powdered metal articles having objects movable within the chambers.

Another object is to provide a process of making chambered articles of powdered metal having objects loose in the chambers, which objects are larger than the outlets to the chambers or which are located in the chambers having no outlets whatever.

Another object is to provide a process of making chambered articles of powdered metal wherein an object is loosely mounted in the chamber with a stem projecting into or through an inlet or outlet of the chamber.

Another object is to provide a process of making chambered articles of powdered metal of the foregoing character wherein the object to be lodged in the chamber is itself previously encased in a core of infiltratable material, this assembly being then pressed Within the interior of a body of powdered metal which is then sintered at a sufficiently high temperature to cause the core to infiltrate into the pores of the metal or to escape through the outlet thereof, leaving the object loose within the chamber left by the departing infiltrat-able material.

The article produced by the process of the present invention is disclosed and claimed in my divisional application hereof, Ser. No. 119,536 filed October 4, 1949, for Chambered Article with Movable Element.

In the drawings:

Figure 1 is a side elevation, partly in section, of an object encased in a core of material which is infiltratable into the powdered metal casing of a ball check valve having inlet and outlet ports;

Figure 2 is a central vertical section through a body of powdered metal containing the coreencased object of Figure 1 prior to sintering;

Figure 3 is a view of the article shown in Figure 2, after sintering and infiltration or expulsion of the infiltratable material;

Figure 4 is a central vertical section through a modified article prior to sintering, similar to that of Figure 2, but lacking passageways leading to the chamber;

Figure 5 is a central vertical section through the article of Figure 4, after sintering has caused the infiltratable core material to disappear into the pores of the powdered metal;

Figure 6 is a top plan view of a further modi- 2 fled core of infiltratable material containing a poppet valve which is to be mounted in a valve chamber within a powdered metal valve block casing;

Figure 7 is a side elevation, partly in central vertical section, of the encased poppet valve of Figure 6;

Figure 8 is a central vertical section through the core-encased poppet valve of Figure '7 embedded in a powdered metal body before sinter- Figure 9 is a central vertical section through the article of Figure 8 after sintering;

Figure 10 is a side elevation, partly in central vertical section, of a further modified core of infiltratable material containing a ball check valve and stem which are to be mounted in a valve chamber having outlet and inlet ports;

Figure 11 is a central vertical section through the core-encased ball check valve and stem embedded in a body of powdered metal before sintering;

Figure 12 is a central vertical section through the completed ball check valve of Figure 11, after sintering;

Figure 13 is a side elevation, partly in central vertical section, of a still further modified coreencased piston which is to be mounted within a powdered metal cylinder;

Figure 14 is a central vertical section through the core-encased. piston of Figure 13 embedded in a powdered metal cylinder before sintering; and

Figure 15 is a central vertical section through the piston and cylinder of Figure 14 after sin tering.

Hitherto, in the metal working arts, it has been difiicult to mount enlarged articles, such as valve members, in chambers having inlets or outlets of smaller diameters than the valve members. Since these valve members could obviously not be inserted through the passageways of smaller diameter, either the valve casing had to be split and reunited, or an access opening formed in the casing of sufl'icient size to admit the valve member, after which the access opening was closed by a plug. Either of these constructions was expensive and left much to be desired from the view point of gas or liquid tightness.

The present invention has solved this problem by encasing the valve member or other object to be placed in the chamber, in a core of infiltrate.- ble material, such as a copper-zinc alloy, and thereafter sintering the assembly at a temperature at which the core metal becomes liquid. During the sintering operation, the core disappears either into the pores of the powdered metal or through the inlet or outlet passageways, leaving the object freely mounted within the chamber, yet of a large size so that it is incapable of escaping through any opening into the chamber. The infiltration of the core metal into the powdered metal body such as powdered iron, increases the hardness and strength thereof. By this process, valve members may be mounted in valve chambers, pistons in cylinders, cams in eccentric bores, and the like.

Referring to the drawings in detail, Figures 1 to 3 inclusive show one form of chambered article, generally designated Ill shown in successive stages of manufacture. The article H)- in its finished form (Figure 3) shown as a ball check valve, consists of a body I l of powdered material, such as powdered iron, having a chamber I2 in the interior thereof in .which:is:mounted a .ball valve member l3 of steel orother suitable,- mat terial which is capable: ofrwithstanding thesintering temperatures and which, at the same-rtime,

is not infiltratable into the pores of the powdered metalof the body H, The ball'valve member I3 is adapted to engage an annular seat- It at the inner end-of a threaded bore 'l5 serving as an inlet port or passage, and a' corresponding threaded bore H5 at the opposite end of thechamber l2 serves as an outlet port or passageand may be provided with a similarseat. l1. As shown in the drawings, the chamber'lziis provided with. a spherical walllB but other'shapes may be produced by thesame iprocessz, It will be observed that the ball H5. is of larger diameter than the passages l5- or I6, yetiby the present invention it is inserted intthe. chamber. 12 .without splitting the body II.

In order to producethechambered article or ball check valve I0, theball 13 of the desired diameter and of suitable material is selected (Figure 1) and provided with a layerxor' core I9 of'infiltratable material, the outer surface 20 of which is of the desired size and configurationfor the inner wall l8 of the'chamber l2. Extending outward from the core l9 are core extensions 2| and 22 corresponding in: size, diameter and configuration to the portsorpassages l5 and [Band similarly" threaded, if threads are desired. The threaded. portions Hand '2 on the extensions 2! and 22 may beformed inthe usual way by means of a threading die or in any other suitable manner.

The core is and its'extensions 2| and 22 may be made from an alloy of 85% copper and'l5 zinc if powdered iron isused forthe body I I. This alloy infiltrateseasily and satisfactorily into the pores of the powdered iron during the sintering operation. In so doing, it increases the: hardness and tensile strength of the :body H, thereby. enhancing thevalue of the :article.

The core assembly, generally designated 25 (Figure 1) containingthe-ball ISembedded in the core I9 and-its extensions 2| and.-22 is then placed in the die cavity of. a conventional molding press; as described in my co-pending application Serial No. 70,056 filed January 10, .1949, for Powdered Metal Article aandiProcess of, Making the Same. The core assembly 25-is;placed in the desired location withintheidie-icavity in the manner described inmy above-.mentioned co-pending application, such as: by placing a quantity of the iron or other metalpowder in the diecavity with its top surfacewat the. desired location, making appropriate allowance for the reduction in size due to the compression of the powdered metal. It will be obvious, however, that if extensions 2| and 22 are employed in connection with the core IS, these extensions must lie far enough inside the powdered metal charge at the beginning of the pressing operationso that the press plunger or plungers will not contact them and possibly break them during the pressing operation. Alternatively, for articles wherein the shape of the die cavity permits, the extensions 2| and 22 may be placed cross-wise or transversely of the die cavity so that they are located as far as possible from the advancing press plungers.

After the core assembly 25 has been properly located. in the die cavity as by the partial filling thereof described above, the die cavity is completely filled with the iron powder up tothe desired level, again taking into account the re ductionin size dueto compression of the'iron powder within the die casting. rdinarily; reduction insize, as'measured by theratio of the spaceuoccupied by the powdered metal to the space occupiedv by the-solid pressed article, is between 2.5 to 1 and 3 to 1, hence the. compression factor must be carefully taken into account in planning the pressing operation.

Alternatively, instead of partially filling the die cavity with powdered metal and then locating the core assembly EEtherein, the core assembly 25 may be held in the desired position within, the die cavity by a suitable fixture (not shown) supportedabove the die cavity during the filling operation. The fixture is then removed when the level of the powdered metalhas risen to a sufficient height around the-core assembly 25 to lodge the latter securely in position without danger of displacement.

After the die cavity has been filled to the-desired level, the press is set in'motion so that its plunger or lplungers enter the die cavity and compress the powdered metal to the desired extent; The semi-finished unsintered article, generally designated 25 (Figure 2) consisting of the core assembly 25 embedded in the pressed but unsintered powdered metal body 2! is then ejected from the die cavity in the manner described in my above-mentioned copending application, whereupon it is ready for sintering and infiltration. The unsintered or green article 26- isv placed in a conventional sintering oven and subjected to a suitable sinterin temperature, the height and time of which are varied in accordance with the size of the article. In the case of a small article such as the check valve 10, sintering'for approximately one-half hour at a temperature of 2020" F. has been found satisfactory. Care must be taken to avoid an excessive temperature or duration of sintering heat beyond that required for the particular size of article, otherwise an undesirable grain structure is set up in the metal. During the s nterin operation, the core alloy I9 infiltrates into the pores of the powdered iron body 27, or escapes through the ponts i5 and I6, as the case may be. llvhen sintering has been completed, the sintered article is cooled down to room temperature under atmospheric-controlled conditions, whereupon it is removed as the finished pieceshown inFlgure3.

The sintering' procedure not only hardensthe iron but the infiltration of the alloy of the core I9 into the pores of the iron imparts additional hardnessand tensile strength there-to, so that an enhanced durability is obtained, in comparison with a powdered iron article which has not been subjected to such infiltration. Upon inspection of the finished article II], it is found that the chamber 12 is hollow, the core alloy having disappeared completely, and of a diameter and configuration substantially indentical With that of the core E9 in which the ball E3 was originally embedded. It is also found that the ball I3 is now loosely mounted in the chamber l2 so that it is free to roll around or rise and fall, and the seats l4 and H are perfectly formed, as well as the threaded portions 28 and 29 thereof, Suitably threaded inlet and outlet pipes may then be threaded into the ports or passages l5 and I3, as these are found to be properly formed by the sintering operation.

The modified chambered article 30 shown in Figures 4 and 5 is the same as the ball check valve of Figure 3, except that the ports or passages l5 and 13 have been omitted. The article 30, however, is formed in the same manner. The article 39 consists of a porous metal block or body 3| having a chamber 32 therein containing a ball or other article 33 which it is desired to mount loosely within the chamber 32.

To produce the chambered article 30, the ball or other object 33 desired to be loosely mounted. in the chamber 32 is coated with a layer 34 of infiltratable material, such as the copper-zinc article 35 having the unsintered body 3! of powdered iron. The latter is then sin-tered in the above-described manner, whereupon the layer 34 or core of infiltratable material disappears into the pores of the body 31, hardening and increasing the tensile strength of the latter, and leaving the ball 33 or other object loosely mounted in the chamber 32. As was previously the case, side wall 38 of the chamber 32 has a diameter corresponding to the diameter of the core 34 of the core assembly 35.

The modified chambered article or valve unit 49 shown in Figures 6 to 9 inclusive, consists of a valve block 4| containing a valve chamber 42 in which is located a valve 43 of the poppet type seated upon an annular beveled seat 44 opening into a port 45. Above the valve 43, a port 46 opens into the chamber 42. The valve 43 has a head 41 and stem 48.

To produce the valve unit 43 shown in Figure 9, a core assembly, generally designated 49, is first prepared, as before, in which the valve 43 is embedded in a core 50 of infiltratable material, such as the copper-zinc alloy previously mentioned. The upper and lower portions 5| and 52 surrounding the head 41 and stem 48 of the valve 43 and the head extension 53 have sizes and configurations corresponding respectively to those desired for the chamber 42 and ports 45 and 46. The portion 52 is joined to the portion 53 by a beveled portion 54 corrwponding in size and configuration to that desired for the valve seat 44.

The core assembly 49 is then placed in a suitable press wherein powdered metal, such as powdered iron, is placed in the die cavity. In order to avoid damaging the valve stem 48, however,

a tubular lower plunger is preferably employed, so as to give clearance for the stem 48. The filling and locating operations are then carried out in the foregoing manner described above. The press plunger or plungers are then operated to compress the metal powder charge into the desired shape or size, thereby producing the semi-finished article 56 shown in Figure 8 and having an unsintered body 5'. surrounding the core assembly 49. After its ejection from the press, the semi-finished article 56 is placed in the sintering oven and subjected to the sintering heat. whereupon the core metal alloy 59 either flows out through the ports 45 and 45 or infiltrates into the pores of the body 51, leav ing the finished valve unit 40 shown in Figure 9. Thus, the valve block 4| attains an increased hardness, not only from the sintering operation, but also from the penetration of the core metal alloy 50 into the pores of the powdered iron.

The modified chambered article 60 shown in Figures 10 to 12 inclusive is generally similar to the check valve unit I E! shown in Figures 1 to 3 inclusive. The ball 63 located in the chamber 52 of the body 6! and seating against the seat 64 closes ports 55 and 66 and has stems 61 and 68 projecting downward and upward respectively through the ports 65 and 66. The core assembly E9 is formed in the same way as the core assembly 25, with a layer or core TD surrounding the ball 63 and its stems 6'! and 68. The process of manufacture is otherwise similar to that described in connection with Figures 1 to 3 inclusive, and similarly requires that the stems 61 and 68 be protected in order not to be crushed by the advancing press plungers. The operations of pressing the unsintered body of powdered metal 'Il around the core assembly 69 to produce the unsintered article l2 are also similar. The sintering also produces the same result, except that the ball 63 in addition to being loosely mounted in the chamber 62 has stems 6! and 68 loosely located in the ports 65 and 66.

The modified chambered article shown in Figures 13 to 15 inclusive consists of a cylinder and piston unit having a cylinder block 3| with a cylinder bore 82 containing a piston head 83 mounted on a piston rod 84. Above the cylinder bore 83 is a chamber 85, and ports and 81 open into the cylinder bore 82 and its extension 85 above and below the piston head 83. The piston rod 34 passes through a partially threaded counterbored opening 88.

To produce the article 80, a core assembly 89 is prepared consisting of the piston head 83 and piston rod 84 surrounded by a layer of unfiltratable material, such as that described above. The core 20 is provided with portions ill, 92 and i3 corresponding respectively to the opening 88, cylinder bore 82 and chamber extension 85. It may also be provided with suitable lateral core projections (not shown) to produce the ports 86 and 87. The latter, however, are so easily drilled that it is preferred to drill them rather than to mold them. hence they are shown in dotted lines in Figure 15.

The core assembly 89 is then placed in a suitable press, as before, located in its proper position, taking into account the compression ratio of the powdered metal, and pressed into the semifinished article shown in Figure 14 and having an unsintered iron body 91. Sintering is then carried out in the foregoing manner, causing the core alloy 90 to be absorbed into the pores of the unsintered powdered metal body 91, or to flow out of the ports 86,8! and 88, as the case may be, leaving the piston head83 loosely mounted for reciprocation in the cylinder bore 82. The extension 85 above the cylinder bore 82 is provided so that the piston head 83 will-not freeze or otherwise tightly adhere to the walls of the cylinder bore 82 during the sintering operation.

Where, as in the form shown in Figures 1 to 3 inclusive, the mold core l9 wholly encases the object I3, the mold core l9 may be made in halves rather than by being cast around the insert. In

the case of the mold core'i9 and in its extensions 2! and 22, the halves may be parted in a plane transverse to the axis of the extensions. This makes the core I9 consist of two identical hollow hemispheres, each carrying a threaded boss. Such a workpiece is easily produced in expensively in large quantities on an automatic screw machine. Obviously, the hemispheres are not necessarily required to fit the object l3 snug ly nor does the hollow within them have to be of regular shape, so long as they are structurally strong enough to withstand the molding pressure without collapsing. So long as this requirement is satisfied, the object l3 may be loose within the core 19, in which case there is also less core metal to be infiltrated.

What I claim is:

1. A process of making a chambered powdered metal article having a body with an insert loosely mounted therein, comprising forming an insert with a shape of. predetermined configuration frommaterial which is not infiltratable into the pores of the powdered metalof the body, embedding the insert in a core of metal infiltratable into thepores of said powdered metal to form a core assembly, forming said-core assembly into a shape having a size and configuration corresponding to the size and configuration desiredfor said chamber, positioning said core assemblyin a mass of powdered metal, compressing said mass containing said core assembly into a body of desired shape to form a semi-finished article, and sintering the semi-finished article at a temperature above the melting point of the core and below the melting point of the insert to effect infiltration of the core material into the pores of said body whereby to leave said insert loosely mounted in said chamber and surrounded by a void previously occupied by the core metal.

2. The process of making a chambered powdered metal article according to claim 1, in which the core is'of metal alloy;

3; The process of making a chambered powdered metal article accordingto claim 1, in which the core is of copper-zinc alloy.

4. A process of making a chambered powdered metal article according to claim 1, in which the body is of pow-dered iron.

5. The process of making a chambered powdered metal article according to'claim 4, in which the core is'of metal alloy.

6. The process of making a chambered powdered metal article according to claim 4, in which the core is of copper-zinc alloy.

7. A process of making a chambered powdered metal article having a body with an insert loosely mounted therein, comprising. forming an insert with a shape of predetermined configuration from material which is not infiltratable into the pores of the powdered metal of the body, embedding the insert in a core of metal infiltratable into the pores of said powdered metal to form a core assembly, forming said core assembly into a shape having a size and configuration corresponding to the size and configuration desired for said chamber, said core also having a smaller diameter extension thereon of infiltratable material positioning said core assembly in a mass of powdered metal with the end of said extension located in a position.corresponding to the ultimate exterior of the article, compressing said mass containing said core assembly into a body of desired shape to form a semi-finished article, and sintering the semi-finished article at a tem perature above the melting point of the core and below the melting point of the insert to effect infiltration of the core material into the pores of said body whereby to leave said insert loosely mounted in said chamber with a passage of smaller diameter than said insert communicating with said chamber from the exterior of said body and surrounded by a void previously occupied by the core metal.

8. A process of making a chambered powdered metal article according to claim 7, in which the core is of metal alloy.

9. The process of making a chambered powdered metal article according to claim 7, in which the core is of copper-zinc alloy.

10. A process of making a chambered powdered metal article according to claim 7, wherein the powdered metal consists predominantly of powdered iron.

JOHN HALLER.

REFERENCES CITED The following references are of record in the file of this 'patent:

UNITED STATES PATENTS Number Name Date 25,998 Evarts Nov. 1, 1859 1,051,814 Lowendahl Jan. 28, 1913 1,188,051 Edstrom et a1 June 20, 1916 2,066,658 Street Jan. 5, 1937 2,180,988 Lemmers etal Nov. 21, 1939 2,227,308 Hildabolt Dec. 31, 1940 2,273,589 Olt 1- Feb. 17, 1942 2,341,860 Ellis Feb. 15, 1944 2,373,405 Lowit Apr. 10, 1945 2,402,120 Boegehold a- June 18, 1946 2,408,430 Lowey Oct. 1, 1946 2,413,512 Morin Dec. 31, 1946 2,422,439 Schwarzkopf June 17, 1947 2,456,779 Goetzel 1- Dec. 22, 1948 2,462,045 WuliT Feb. 15, 1949 2,561,579 Lenel July 24, 1951 FOREIGN PATENTS Number Country Date 452,503 Great Britain Aug. 17, 1936 573,740 Great Britain Dec. 4, 1945 611,466 Great Britain Oct. 29, 1948 

1. A PROCESS OF MAKING A CHAMBERED POWDERED METAL ARTICLE HAVING A BODY AN INSERT LOOSELY MOUNTED THEREIN, COMPRISING FORMING AN INSERT WITH A SHAPE OF PREDETERMINED CONFIGURATION FROM MATERIAL WHICH IS NOT INFLITRABLE INTO THE PORES OF THE POWDERED METAL OF THE BODY, EMBEDDING THE INSERT IN A CORE OF METAL INFLITRABLE INTO THE PORES OF SAID POWDERED METAL TO FORM A CORE ASSEMBLY, FORMING SAID CORE ASSEMBLY INTO A SHAPE HAVING A SIZE AND CONFIGURATION CORRESPONDING TO THE SIZE AND CONFIGURATION DESIRED FOR SAID CHAMBER, POSITIONING SAID CORE ASSEMBLY IN A MASS OF POWDERED METAL, COMPRESSING SAID MASS CONTAINING SAID CORE ASSEMBLY INTO A BODY OF DESIRED SHAPE TO FORM A SEMI-FINISHED ARTICLE, AND SINTERING THE SEMI-FINISHED ARTICLE AT A TEMPERATURE ABOVE THE MELTING POINT OF THE CORE AND BELOW THE MELTING POINT OF THE INSERT TO EFFECT INFILTRATION OF THE CORE MATERIAL INTO THE PORES OF SAID BODY WHEREBY TO LEAVE SAID INSERT LOOSELY MOUNTED IN SAID CHAMBER AND SURROUNDED BY A VOID PREVIOUSLY OCCUPIED BY THE CORE METAL.
 7. A PROCESS OF MAKING A CHAMBER POWDERED METAL ARTICLE HAVING A BODY WITH AN INSERT LOOSELY MOUNTED THEREIN, COMPRISING FORMING AN INSERT WITH A SHAPE OF PREDETERMINED CONFIGURATION FROM MATERIAL WHICH IS NOT INFILTRATABLE INTO THE PORES OF THE POWDERED METAL OF THE BODY, EMBEDDING THE INSERT IN A CORE OF METAL INFILTRABLE INTO THE PORES OF SAID POWDERED METAL TO FORM A CORE ASSEMBLY, FORMING SAID CORE ASSEMBLY INTO A SHAPE HAVING A SIZE AND CONFIGURATION CORRESPONDING TO THE SIZE AND CONFIGURATION DESIRED FOR SAID CHAMBER, SAID CORE ALSO HAVING A SMALLER DIAMETER EXTENSION THEREON IN INFILTRATABLE MATERIAL POSITIONING SAID CORE ASSEMBLY IN A MASS OF POWDERED METAL WITH THE END OF SAID EXTENSION LOCATED IN A POSITION CORRESPONDING TO THE ULTIMATE EXTERIOR OF THE ARTICLE, COMPRESSING SAID MASS CONTAINING SAID CORE ASSEMBLY INTO A BODY OF DESIRED SHAPE TO FORM A SEMI-FINISHED ARTICLE, AND SINTERING THE SEMI-FINISHED ARTICLE AT A TEMPERATURE ABOVE THE MELTING POINT OF THE CORE AND BELOW THE MELTING POINT OF THE INSERT TO EFFECT INFILTRATION OF THE CORE MATERIAL INTO THE PORES OF SAID BODY WHEREBY TO LEAVE SAID INSERT LOOSELY MOUNTED IN SAID CHAMBER WITH A PASSAGE OF SMALLER DIAMETER THAN SAID INSERT COMMUNICATING WITH SAID CHAMBER FROM THE EXTERIOR OF SAID BODY AND SURROUNDED BY A VOID PREVIOUSLY OCCUPIED BY THE CORE METAL. 